DESCRIPTION

The PPI::Document class represents a single Perl "document". A PPI::Document object acts as a root PPI::Node, with some additional methods for loading and saving, and working with the line/column locations of Elements within a file.

The exemption to its PPI::Node-like behavior this is that a PPI::Document object can NEVER have a parent node, and is always the root node in a tree.

Storable Support

PPI::Document implements the necessary STORABLE_freeze and STORABLE_thaw hooks to provide native support for Storable, if you have it installed.

However if you want to clone clone a Document, you are highly recommended to use the internal $Document->clone method rather than Storable's dclone function (although dclone should still work).

METHODS

Most of the things you are likely to want to do with a Document are probably going to involve the methods from PPI::Node class, of which this is a subclass.

The methods listed here are the remaining few methods that are truly Document-specific.

new

The new constructor takes as argument a variety of different sources of Perl code, and creates a single cohesive Perl PPI::Document for it.

If passed a file name as a normal string, it will attempt to load the document from the file.

If passed a reference to a SCALAR, this is taken to be source code and parsed directly to create the document.

If passed zero arguments, a "blank" document will be created that contains no content at all.

In all cases, the document is considered to be "anonymous" and not tied back to where it was created from. Specifically, if you create a PPI::Document from a filename, the document will not remember where it was created from.

The constructor also takes attribute flags.

At this time, the only available attribute is the readonly flag.

Setting readonly to true will allow various systems to provide additional optimisations and caching. Note that because readonly is an optimisation flag, it is off by default and you will need to explicitly enable it.

get_cache

If a document cache is currently set, the get_cache method will return it.

Returns a PPI::Cache object, or undef if there is no cache currently set for PPI::Document.

readonly

The readonly attribute indicates if the document is intended to be read-only, and will never be modified. This is an advisory flag, that writers of PPI-related systems may or may not use to enable optimisations and caches for your document.

Returns true if the document is read-only or false if not.

tab_width [ $width ]

In order to handle support for location correctly, Documents need to understand the concept of tabs and tab width. The tab_width method is used to get and set the size of the tab width.

At the present time, PPI only supports "naive" (width 1) tabs, but we do plan on supporting arbitrary, default and auto-sensing tab widths later.

Returns the tab width as an integer, or dies if you attempt to set the tab width.

save

$document->save( $file )

The save method serializes the PPI::Document object and saves the resulting Perl document to a file. Returns undef on failure to open or write to the file.

serialize

Unlike the content method, which shows only the immediate content within an element, Document objects also have to be able to be written out to a file again.

When doing this we need to take into account some additional factors.

Primarily, we need to handle here-docs correctly, so that are written to the file in the expected place.

The serialize method generates the actual file content for a given Document object. The resulting string can be written straight to a file.

Returns the serialized document as a string.

hex_id

The hex_id method generates an unique identifier for the Perl document.

This identifier is basically just the serialized document, with Unix-specific newlines, passed through MD5 to produce a hexadecimal string.

This identifier is used by a variety of systems (such as PPI::Cache and Perl::Metrics) as a unique key against which to store or cache information about a document (or indeed, to cache the document itself).

Returns a 32 character hexadecimal string.

index_locations

Within a document, all PPI::Element objects can be considered to have a "location", a line/column position within the document when considered as a file. This position is primarily useful for debugging type activities.

The method for finding the position of a single Element is a bit laborious, and very slow if you need to do it a lot. So the index_locations method will index and save the locations of every Element within the Document in advance, making future calls to <PPI::Element::location> virtually free.

Please note that this index should always be cleared using flush_locations once you are finished with the locations. If content is added to or removed from the file, these indexed locations will be wrong.

flush_locations

When no longer needed, the flush_locations method clears all location data from the tokens.

normalized

A "normalized" Perl Document is an arbitrary structure that removes any irrelevant parts of the document and refactors out variations in style, to attempt to approach something that is closer to the "true meaning" of the Document.

See PPI::Normal for more information on document normalization and the tasks for which it is useful.